Trigger system

ABSTRACT

A trigger system for a firearm includes a fully adjustable trigger housing assembly which can be preassembled before insertion into the firearm receiver. Adjustments for the trigger system include a trigger tension adjustment, a hammer connector adjustment, a trigger take-up adjustment, and a trigger backlash adjustment.

United States Patent 1191 1111 3,863,375 Browning Feb. 4, 1975 TRIGGER SYSTEM 1,996,124 4/1935 Rowley 42/75 c 2,203,378 6/1940 Browning. 42/42 R [75 Inventor. Bruce W. Browning, Ogden, Utah 3,380,182 4/1968 Browning u 42/75 C [73] A i B i Arms Company, Morgan 3,710,495 1/1973 Ziegler et a1 42/75 C Utah Primary Examiner-Benjamin A. Borchelt [22] Ffled: July 1973 Assistant Examiner-C. T. Jordan [21] Appl, No,; 378,952 Attorney, Agent, or Firm-Trask & Britt 52 11.8. c1. 42/69.R, 42/75 0 1 AB STRAC T 51 1111. C1. F41c 19/00 A trlgger System for a firearm Includes a fully 1 [58] Field of Search 42/75 c, 69 R, 69 B, 69A, able trigger housing assembly which can be preassem- 42 23 24 5 41 42 R bled before insertion into the firearm receiver. Adjustments for the trigger system include a trigger tension [56] Referen Cit d adjustment, a hammer connector adjustment, a trigger UNITED STATES PATENTS take-up adjustment, and a trigger backlash adjust- 33,371 9/1861 Smith .1 42/69 R ment' 5 9 Claims, 6 Drawing Figures 11/1910 Clement PATENTEUFEB 3.863.375

- SHEET 10F 3 TRIGGER SYSTEM BACKGROUND OF THE. INVENTION 1. Field: The presentiinvention relates to a trigger system for firearms and, more particularly, to atrigger system for rifles or handguns.

arms, a fine trigger is often referred to as a hairtrig ger, meaningthat it need move only slightly to cause the weapon to fire. Hairtriggers are generally regarded as undesirable andunsafe. On the other hand, trigger systems having a numberof adjustments incorportated thereinto have heretofore required-a-rather complex and prolonged assembly operation. I

Accordingly, an object of the present invention is to provide a fully adjustabletrigger system yet one which is readily and quickly-assembled or-takendown.

SUMMARY OF THE INVENTION The trigger system of the invention includes a sear having a first notch for holdingthe' firearms hammer in a half cock position andsecond notch for holding the hammer in a fully cockedp'ositionThesystem may include a first, nonadjustable biasing means which provides a minimum safe bias on the sear to hold it against the hammer, and a second, adjustable, biasing means for adjustably biasing the seal-against the hammer. The

means connectingthe firearms trigger to the sear may include aconnector link which isarranged to disengage the sear from the hammer in response to pullingon thetrigger. Thetriggerspring is arranged to bias the connector toward the sear, and an adjustment may be included to vary the biased position or direction'of the connector.

The trigger system, as described hereinafter, can be assembled to a trigger housing so that it maybe slipped, fully assembled, into the.firearms-receiver. Apair of mainsprings can be used, and the trigger housing. is configurated to provide clearance for associated mainspring guides, .mainspringsv and pins.

BRIEF DESCRIPTIONIOF THE-DRAWINGS FIG. 1 is-an explodedv pictorial viewshowing a trigger.

mechanism according to-the invention;

- FIG. 2 is a cross sectional 'viewof the mechanism of FIG. 4 is a cross sectional view taken in the same plane as FIG. 2, but showing the mechanism in still another position;

FIG. 5 is a side elevation of the trigger housing illustrated in FIG. 1 with the associated mainsprings in their operative position; and

FIG. 6 is a sectional detail through one side of the trigger housing illustrated in FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The trigger mechanism of FIG. I is shown in conjunction with a rifle having a butt stock 9, a hammer 10, and a breech block 11. Since the present invention concerns essentially only the-trigger mechanism, the remainder of the rifle is not shown and may be regarded as conventional. Although a rifle is suggested by the drawings, theinventive mechanism may obviously be utilized with other types of firearms.

The trigger mechanism includes a trigger housing generally designated 13in FIG. 1 which is fitted into a receiver 14 (see FIGS. 2 4) which is, in turn, connected at one end to the butt stock 9 and at the other end to a barrel (not shown). Although the receiver is not fully. illustrated, it may be regarded as a conventional housing-for the trigger mechanism, the hammer and other components. For present purposes, the receiver may be understood to include the recess 12 formed in the forward end of the butt stock 9 which surrounds and supports the trigger housing as will be hereinafter described. Commonly assigned, copending U.S. Pat. application Ser. No. 360,6l9, filed May 16,

- tionship, one pair above the other. The vertical slot 17 defined between the cars 15, 16 serves as a guide for a connector 18, as will be described in detail hereinafter. The V-shaped notches 19'on either side of the trigger housing between the corresponding ears of the respective pairs serve to seat the mainspring spacer 20 (a short tubular member), as will also be described in detail hereinafter. The trigger housing is held stationary FIG. 1 in assembled condition, theycross section'being taken in a vertical'plane through the axis oflthe mechanism of FIG. 1',

FIG. 3 is a cross sectional view-taken in thesame plane as FIG. 2, but showing the mechanism in another position;

in the buttstock recess 12 by a bolt 21 (see FIGS. 2 and 3) which extends through the butt stock and threads into the rear of the trigger housing.

As shown, and inverted, L-shaped trigger 22 is pivotally held in the trigger housing between the lower set of ears 16a and 16b by pivot pin 23 so that it pivots at its vertex. The foot'22a of the trigger extends rearward and thus moves in a vertical are within the trigger housing when the trigger is pulled or released. The upper surface of the trigger foot 22a is shown with a horizontally extending slot 24 formed therein, into which is pivotally connected the aforementioned connector 18. The connector l-Sextends up through the aforementioned vertical slot 17 in the trigger housing between the housing cars 15, 16. The lower, pivoted end of the connector 18 is formed as afoot 26 which extends for-- In the illustrated arrangement, a spiral-wound trigger spring 29 is slidably disposed over the trigger pin 23. The opposed ends 30a and 30b of the trigger spring extend in the same direction and are placed so that they ordinarily bias the trigger forward. (In other words, the spring 29 urges the trigger 22 to rotate clockwise in the drawings.) More particularly, the end 30b of the spring 29 presses against the top of the trigger. The connector is urged to pivot counterclockwise by a connector spirng 31 until its foot 26 abuts the end of an adjustment screw 32 (called the connector screw) which extends up through the trigger 22. The connector screw 32 acts as a forward stop to the connector 18 and may be adjusted to allow the connector to contact a sear (43 described hereinafter) in the proper manner.

The trigger 22 is selectively stopped from pivoting forward or clockwise by a trigger take-up 34 which is threaded into the bottom of the trigger housing 13. In the illustrated arrangement (see FIGS. 2 and 3), a lip 36 on the end of the trigger foot 22a catches the head 37 of the take-up screw 34, thereby being stopped from pivoting further. The lip 36 is at the top of a slot formed in the rear face of the trigger foot, and is thus hidden in FIG. 1. The distance which the take-up screw 34 is threaded into the trigger housing governs the forward stop position of the trigger.

The travel of the trigger in the rearward, or counterclockwise, direction is determined by a backlash" adjusting screw 38 which is threaded through the foot 22a of the trigger 22. The trigger can be pulled back until the tip of the backlash screw 38 abuts the surface 13a of the trigger housing 13. The further the backlash screw is threaded through the trigger foot, the less the distance the trigger can pivot back. In practice, the backlash screw is desirably adjusted to stop the rearward movement of the trigger just after the trigger has released the hammer from the full cock position.

The hammer catch mechanism includes a V-'shaped sear, generally designated 43, which is rotatably mounted between the upper pair of trigger housing ears a and 15b by pivot pin 44. The sear is positioned so that one of its legs 43a extends back over the trigger housing adjacent the upper end of the connector link 18 and its other leg 43b extends downward into the receiver adjacent the rear of the hammer 10. The end of the rearwardly extending leg 43a of the sear has a horizontally extending groove 47 formed therein. A pin 45 (called the sear spring rest pin) extends through the sear in front of and parallel the groove 47. The ends of the sear spring rest pin 45 extend slightly to either side of the sear. (The sides of the sear are hereinafter referred to as the left and right sides, the left side being the one which can be seen in the drawings.) Across the end of the sear spring rest pin 45 which extends from the right side of the sear is placed the extended end wire 51a of a spiral-wound spring 51 (called the sear spring). The spring 51 is mounted about a pin 52 (called the sear spring pin) fitted through the side walls 53a and 53b of the housing 13. The side walls 530 and 53b define a groove 54 across the top of the trigger housing 13 which retains the other end wire 51b of the sear spring 51. Accordingly, the sear spring 51 urges the sear 43 to rotate in the clockwise 'direction.

As best illustrated by FIGS. 1 and 6, ends of rest pin 45 are received by relief cuts 45a in the side walls 53a and 53b of the trigger housing 13. A trigger pull adjustment member 55 is mounted to pivot on'pin 52 with one end 55a of the member atop the rest pin 45. As shown, the bias of the member 55 is adjustable whereas that of the sear spring is not.

Refereing to FIG. 6, a vertical bore 56 is formed through the trigger housing side wall, and a cylindrical spring guide member 57 is slidably installed therein. A spring 58 is installed in the bore 56 between the spring guide 57 and the end 55b of the trigger pull adjustment member 55. A portion 57a of the spring guide 57 is of reduced diameter to fit within the coils of the spring 58. The bias applied by the member 55 to the sear end 43a is adjusted by turning screw 59 to raise the spring guide 57 in the bore 56. In effect, the member 55 duplicates the function of the sear spring 5], but it is the sear spring 51 which provides a minimum bias to the sear, thereby effectively inhibiting hairtrigger" adjustments.

Without the biasing force of the sear spring 51, the sear 43 should rotate freely. Its clockwise rotation is stopped when its rearwardly directed leg 43a strikes a pin 61 (called the "trigger housing pin") which is secured traversely across the bifurcated front wall of the trigger housing 13. Ordinarily, the downwardly extending leg 43b of the sear 43 is biased against the back of the hammer 10 by the springs 51 and 58.

The trigger mechanism described (i.e., the trigger housing, together with the parts pivotally connected thereto) can be assembled apart from the firearm. The trigger mechanism is then slipped, fully assembled, into the receiver and held in place by the mainspring pin 63b urged back into the V-slot 19 by the mainsprings 71a and 71b, as shown in FIG. 5. Guide rails 64 formed integral with the trigger housing sidewalls ride in corresponding slots 65 in the receiver sides to properly position the trigger mechanism therein. For ease of assembly, the rails 64 are desirably tapered downward from a narrow upper end, as shown. The pin 61 is inserted into the trigger housing until its ends are flush with the outside surfaces of the rails 64. The combined width of the pin 61 and rails 64 is slightly less than the width of the slots 65. A recess 65a is provided in each slot 65, and the trigger housing is inserted until the ends of pin 61 align with these recesses 65a. The housing 13 then moves slightly rearward to seat the pin 61. The entire mechanism is held temporarily in position by the force transferred by the mainsprings 71a and 71b to the trigger housing 13. Once in position in the receiver, the butt stock bolt 21 can be threaded into the rear of the trigger housing to hold it securely in place.

The structure and function of the trigger and mainsprings are best understood by considering FIGS. 2 4 which consecutively show the uncocked, fully cocked, and haf cocked positions of the hammer. In the illustrated arrangememt, the forward face of the downwardly extending leg of the trigger sear 43 is tapered slightly off-vertical and has a notch 66 formed therein. The taper of the sear generally is tangent to the configuration of the back of the hammer, which is convex when viewed from the side. The hammer is pivoted at pivot pin 68 and the curvature of the back of the hammer is not quite circular with respect to the hammer pivot point. Accordingly, the sear 43, which is biased to pivot clockwise against the back of the hammer 10 by the sear spring 51, pivots with the hammer. The hammer can be cocked manually or it may be forced back, for example, by the pressure of the breech block 11 against the hammer roller 72 when the breech block is moved; e.g., by a lever-action mechanism of the type described in the aforesaid copending patent application Ser.'No. 360,6l9 now U.S. Pat. No. 3,830.000.

The two mainsprings 71a and 71b, respectively, are the illustrated means which drive the hammer forward (i.e., the mainsprings pivot the hammer in counterclockwise direction). The mainsprings shown are spiral compression springs which are slidably fitted about an associated pair of guide rods 73a and 73b. The guide rods are mounted to pivot and to telescope, within limits, in the mainspring pivot pins 63, which are in turn rotatably mounted at the opposite ends of the guide rods. The pin 63aat'the forward ends of the rods is mounted in a channel 74 (FIG. 1) formed through the hammer, and extends from both sides of the hammer. The pin ends are apertured 75a to slidably receive the forward ends of the guide rods 73and 73b so that in assembled condition, the mainsprings 71a and 71b are held on opposite sides of the hammer 10.

In the illustrated embodiment (see particularly FIGS. 1 and 5) the forward'ends of the mainspring guide rods 73a and 73b have collars 76 formed thereon against which the mainsprings 71a and 71b press. The collars stop the guide rods from slipping forward; the rear ends of the guide rods have no collar, and can thus telescope back through apertures 75b in the mainspring pin 63b which is seated against the trigger housing 13. The guide rods 73a and 73b extend back on either side of the connector 18 through grooves 77 formed at the back of the V-shaped notches 19. With the mainsprings under compression, the guide rods 73a and 73b extend into circular recesses 78 formed in the sides of the trigger housing 13. The mainsprings and associated guide rods are thus provided with amplespace within which to function.

The functioning of the mainsprings is relatively uncomplicated; As the hammer falls, the pins 63 turn slightly and the rearward ends of the guide rods 73a and 73b withdraw slightly from the associated apertures 75b in the pin 63b at the trigger housing 13. Concomitantly, the mainsprings 71a and 71b extend in length. When the hammer is cocked back, the opposite occurs; the guide rods 73a and 73b slide into the apertures 75b in the back pin 63b, and the mainsprings 71a and 71b are put into compression. FIG. 5 shows one of the mainsprings 71a pivoted and compressed in phantom lines.

The hammer 10, as illustrated in FIGS. 3 and 4, has two catch (cocked) positions. The positions are respectively called the full cock and half cock positions. The half cock position (FIG. 4) occurs when the notch 81 (catch means) on the hammer catches in the first notch 66 in the sear 43. When the hammer is in the half cock position, the gun is on safe, and the trigger will not release thehammer (because the upper end of the connector 18 is not under the lip 46 on the rearwardly extending leg of the sear). The half cock sear notch 66 also functions as a safety mechanism during manual cocking of the hammer, in that if the thumb should slip during manual cocking, the sear notch 66 will catch the hammer at the half cock position. If the trigger is pulled, the notch 66 is pivoted out of registering position with the hammer notch 81 to permit the hammer 10 to fall.

In the full cock position (FIG. 3), the gun is ready .to be fired. The full cock position occurs when the hammer is forced completely back, thereby pivoting the sear 43 counterclockwise until the sharp lower end 82 of the sear catches in the hammer notch 81 as shown. When the sear 43 pivots counterclockwise, it also pushes the connector 18 back slightly to an energized position against the trigger spring 29. Accordingly, the connector is automatically urged to pivot under the sear lip 46 when the sear end is pivoted (i.e., raised) sufficiently by the urging of the hammer. The trugger take-up screw 34 should be adjusted so that the trigger need not move back excessively before the connector contacts the sear; if the trigger were set too far forward, the connector 18 would not pivot forward (counterclockwise) and catch under the sear lip 46 when the full cock position was reached. The trigger take-up screw 34 should also position the trigger far enough forward to allow the connector to disconnect from the sear in the half cock position; otherwise, the connector could never release the sear, and the sear could never move into half cock position.

Pulling the trigger 22 releases the hammer 10 from full cock. As the trigger foot 22a rises, so does the connector 18 which, in turn, pivots the sear 43. The sear pivots until it is no longer caught in the hammer notch 81; and then the mainsprings 71a and 71b drive the hammer forward to strike the rear of the breech block 11 to impart firing energy to the firing pin 83 (FIG. 1).

I claim:

1. A trigger system for a firearm comprising:

a trigger housing;

a hammer, pivotally mounted to said housing and carrying catch means;

a scar, carrying a first lock means for holding the hammer in a half cock position and a second lock means for holding the hammer in a fully cocked position, pivotally mounted to said housing to register respective said lock means with said catch means when said hammer is pivoted to half cock and full cock positions, respectively; a trigger pivotally mounted to said housing;

means operably connecting said trigger to said sear to release the hammer from said fully cocked position upon pulling the trigger;

nonadjustable bias means mounted to provide a selected minimum bias of said sear against said hammer; and

second, adjustable bias means mounted for adjustment to additionally bias said sear against said hammer.

2. A trigger system according to claim 1 wherein said connecting means includes a connector link pivotally connected to said trigger and arranged to disengage said sear from said hammerby pulling said trigger.

' 3. ,A trigger system according to claim 2 including means arranged to bias said connector link toward said sear.

4. A trigger system according to claim 1 further including a pair of mainsprings and means for seating said mainsprings on said trigger housing for pivotal motion relative thereto, said mainsprings being arranged to extend on the sides of the hammer and connected thereto to drive the hammer upon its release by said sear.

5. A trigger system for a firearm comprising:

a trigger housing;

a hammer, pivotally mounted to said housing and carrying catch means;

a sear, carrying a first lock means for holding a hammer in a half cocked position and a second lock means for holding a hammer in a fully cocked position, pivotally mounted to said housing to register respective said lock means with said catch means when said hammer is pivoted to half cock and full cock positions, respectively;

a trigger pivotally mounted to said housing;

a connector link pivotally connected to said trigger and arranged to disengage said sear from said hammer by pulling said trigger;

means arranged to bias said connector link towards said sear; and

connector adjustment means which abut said connector link and which are selectively adjustable to vary the biased position of said connector link.

6. A trigger system according to claim wherein said connector link includes a foot positioned above said trigger, and said connector adjustment means includes an abutment screw threaded through said trigger to abut against said foot, thereby to adjust the biased position of said link.

7. A trigger mechanism for a firearm having a receiver and a hammer comprising:

a trigger housing member with external rails for guiding said housing into assembled position in the receiver of the firearm;

a trigger, pivotally connected to said housing;

a scar which is pivotally connected to said housing and which has a first lock means for holding the firearm hammer in a half cock position and a second lock means for holding the hammer in a full cock position;

means operably connected between said trigger and said sear in said housing for releasing said sear from said hammer in full cock position upon actuation of said trigger;

said trigger housing being insertable in said firearm with said sear. said hammer, and said connecting means all preassembled therein;

nonadjustable bias means mounted to provide a selected minimum bias of said sear against said hammer; and

second, adjustable bias means mounted for adjustment to additionally bias said sear against said hammer.

8. A trigger system according to claim 7 further including a pair of mainsprings and means for seating said mainsprings on said trigger housing for pivotal motion relative thereto, said mainsprings being arranged to extcnd on the sides of the hammer and connected thereto to drive the hammer upon its release by said sear.

9. In a firearm including a trigger housing mounted within a receiver thereof and a sear, trigger, linking means, and mainspring all mounted in operable arrangement within said trigger housing to operate and control the cocking and firing action of a hammer, the improvement which comprises:

pivotally mounting said sear, trigger, and linking means within said trigger housing; substantially vertical rails on the outer walls of said housing tapering to a narrower width at the top; pin means transversely mounted in said trigger housing with its respective ends terminating approximately flush with the outside edges of said vertical rails and projecting rearward from said rails; corresponding vertical slots within the receiver arranged to receive said vertical rails and including recesses arranged to receive the end portions of said pin means when said trigger housing is installed in said receiver; means adapted to bear against one end of said mainspring and transmit the force thereof to said trigger housing thereby temporarily to hold said trigger housing in place; and means for permanently securing said housing in said receiver. 

1. A trigger system for a firearm comprising: a trigger housing; a hammer, pivotally mounted to sAid housing and carrying catch means; a sear, carrying a first lock means for holding the hammer in a half cock position and a second lock means for holding the hammer in a fully cocked position, pivotally mounted to said housing to register respective said lock means with said catch means when said hammer is pivoted to half cock and full cock positions, respectively; a trigger pivotally mounted to said housing; means operably connecting said trigger to said sear to release the hammer from said fully cocked position upon pulling the trigger; nonadjustable bias means mounted to provide a selected minimum bias of said sear against said hammer; and second, adjustable bias means mounted for adjustment to additionally bias said sear against said hammer.
 2. A trigger system according to claim 1 wherein said connecting means includes a connector link pivotally connected to said trigger and arranged to disengage said sear from said hammer by pulling said trigger.
 3. A trigger system according to claim 2 including means arranged to bias said connector link toward said sear.
 4. A trigger system according to claim 1 further including a pair of mainsprings and means for seating said mainsprings on said trigger housing for pivotal motion relative thereto, said mainsprings being arranged to extend on the sides of the hammer and connected thereto to drive the hammer upon its release by said sear.
 5. A trigger system for a firearm comprising: a trigger housing; a hammer, pivotally mounted to said housing and carrying catch means; a sear, carrying a first lock means for holding a hammer in a half cocked position and a second lock means for holding a hammer in a fully cocked position, pivotally mounted to said housing to register respective said lock means with said catch means when said hammer is pivoted to half cock and full cock positions, respectively; a trigger pivotally mounted to said housing; a connector link pivotally connected to said trigger and arranged to disengage said sear from said hammer by pulling said trigger; means arranged to bias said connector link towards said sear; and connector adjustment means which abut said connector link and which are selectively adjustable to vary the biased position of said connector link.
 6. A trigger system according to claim 5 wherein said connector link includes a foot positioned above said trigger, and said connector adjustment means includes an abutment screw threaded through said trigger to abut against said foot, thereby to adjust the biased position of said link.
 7. A trigger mechanism for a firearm having a receiver and a hammer comprising: a trigger housing member with external rails for guiding said housing into assembled position in the receiver of the firearm; a trigger, pivotally connected to said housing; a sear which is pivotally connected to said housing and which has a first lock means for holding the firearm hammer in a half cock position and a second lock means for holding the hammer in a full cock position; means operably connected between said trigger and said sear in said housing for releasing said sear from said hammer in full cock position upon actuation of said trigger; said trigger housing being insertable in said firearm with said sear, said hammer, and said connecting means all preassembled therein; nonadjustable bias means mounted to provide a selected minimum bias of said sear against said hammer; and second, adjustable bias means mounted for adjustment to additionally bias said sear against said hammer.
 8. A trigger system according to claim 7 further including a pair of mainsprings and means for seating said mainsprings on said trigger housing for pivotal motion relative thereto, said mainsprings being arranged to extend on the sides of the hammer and connected thereto to drive the hammer upon its release by said sear.
 9. In a firearm including a trigger housing moUnted within a receiver thereof and a sear, trigger, linking means, and mainspring all mounted in operable arrangement within said trigger housing to operate and control the cocking and firing action of a hammer, the improvement which comprises: pivotally mounting said sear, trigger, and linking means within said trigger housing; substantially vertical rails on the outer walls of said housing tapering to a narrower width at the top; pin means transversely mounted in said trigger housing with its respective ends terminating approximately flush with the outside edges of said vertical rails and projecting rearward from said rails; corresponding vertical slots within the receiver arranged to receive said vertical rails and including recesses arranged to receive the end portions of said pin means when said trigger housing is installed in said receiver; means adapted to bear against one end of said mainspring and transmit the force thereof to said trigger housing thereby temporarily to hold said trigger housing in place; and means for permanently securing said housing in said receiver. 